You can download the DLCs here https://technohackerblog.blogspot.com/2014/12/ms-flight-dlcs.html
Extract them to your installation folder of Microsoft Flight
open the FileLocator.config with notepad and find this line : VirtualPath="HawaiianAdventurePack" />
rename "HawaiianAdventurePack" with "Hawaii"
That's it! I hope it works for you.